去美国旅游的中国人减少了

per – prep. for each

challenge – n. a call to take part in a competition; a test

dip - n. a drop or decrease

hospitality – n. the warm welcome and friendly treatment of visitors and strangers

management – n. the process of dealing with or controlling things

substitute – n. replacement; something to take the place of something else

harassment – n. aggressive pressure

discount – n. an amount taken off the usual price; a price reduction

setback – n. a problem that makes progress more difficult or success less likely